The present invention concerns a two-port solenoid valve for hydraulic or pneumatic fluid, of the type involving an excitation coil capable of being supplied electrically, mounted inside a magnetic circuit in the form of a can or pot and held by a pole washer, as well as a fluid circuit with an intake orifice, at least one discharge orifice and an internal passage capable of being closed or opened by a movable check-valve element, subject to the effect of the pressure of the fluid admitted through the inlet orifice and to the magnetic field generated by the excitation coil when the latter is supplied electrically.
In a two-port solenoid valve of this type, of known design, closure of the internal passage is obtained either by means of a simple ball or by means of a conical or spherical flap. In both cases it is necessary to effect a very precise machining of the fixed internal zone, or fixed seat, that comes in contact, depending on the case, with the ball or with the conical or spherical flap to obtain a tight contact in the closed position of the solenoid valve. It is also necessary to observe a very high machining precision to guarantee the coaxiality of the said internal passage on the one hand and the guidance zone of the ball or conical or spherical flap on the other. Thus, obtaining a satisfactory functioning has required a precise and costly fabrication of the solenoid valve components, with relatively tight dimensional tolerances.
Furthermore, the conical or spherical internal forms of the known valve elements have made it very difficult to reduce the overall dimensions of the valve, and/or to reduce the energy required for its functioning.
Additionally, during the closure of a known solenoid valve of the type involved the occurrence of misalignment of the closure element such as a ball or conical flap has caused slippage, thus frictional stress, between the first contact of the closure element with the fixed seat and a complete closure. Accelerated wear of the internal parts of the solenoid valve has thus resulted.